Determination of touch and hover is important for detecting interaction with a system. In recent years, capacitive touch sensors for touch screens have gained in popularity, in addition to the development of multi-touch technologies. A capacitive touch sensor comprises rows and columns of conductive material in spatially separated layers (sometimes on the front and back of a common substrate). To operate the sensor, a row is stimulated with an excitation signal. The amount of coupling between each row and column can be affected by an object proximate to the junction between the row and column (i.e., taxel). In other words, a change in capacitance between a row and column can indicate that an object, such as a finger, is touching the sensor (e.g., screen) near the region of intersection of the row and column. By sequentially exciting the rows and measuring the coupling of the excitation signal at the columns, a heatmap reflecting capacitance changes, and thus proximity, can be created.
Generally, taxel data is aggregated into heatmaps. These heatmaps are then post-processed to identify touch events, and the touch events are streamed to downstream processes that seek to understand touch interaction, including, without limitation, gestures, and the objects in which those gestures are performed. These systems and methods are generally directed to multi-touch sensing on planar sensors. Obtaining information to understand a user's touch, gestures and interactions with an object introduces a myriad of possibilities, but because handheld objects, for example, come in a multitude of shapes, it can be difficult to incorporate capacitive touch sensors into objects such as a controller, ball, stylus, wearable device, and so on, so that the sensors can thereby provide information relative to a user's gestures and other interactions with the handheld objects.
While fast multi-touch sensors enable faster sensing on planar and non-planar surfaces, they can have reduced capabilities in providing detailed detection of non-contact touch events occurring more than a few millimeters from the sensor surface. Fast multi-touch sensors can also have reduced capabilities in providing detailed information relative to the identification, and/or position and orientation of body parts (for example, the finger(s), hand, arm, shoulder, leg, etc.) while users are performing gestures or other interactions.